The invention relates to a quartz controlled analog watch having a quartz controlled pulse generator for delivering minute pulses and an indexing means mounted for rotation about an axis and for directly driving a minute wheel through the intermediary of an indexing device, said indexing means being adapted to be deflected from a position of rest by means of a coil to which output pulses from the pulse generator have been applied, and a permanent magnet, one of which is stationarily mounted and the other on the indexing means, and to be returned by a return spring.
Such a watch is described in German Offenlegungsschrift No. 2,617,077 and U.S. Pat. No. 4,128,992 issued Dec. 12, 1978 to Egger et al, both belonging to the Applicants' assignee, and the disclosure of these publications is incorporated herein by reference. In this known watch, the smallest unit indicated is the minute, which is the reason why the indexing means directly drives a minute wheel. The watch has the advantage of being extremely simple and robust in its design, and at the same time highly accurate in its indication.
The object underlying the invention was to provide such a watch with a second hand, and yet involving lower cost than in the known watches where the second wheel drives the minute wheel by way of an intermediate drive. Starting with a quartz controlled analog watch of the kind mentioned at the beginning, this object is attained in accordance with the invention in that the pulse generator is designed to deliver minute pulses and other time pulses weaker in energy than the minute pulses, the pulse series frequency of said other time pulses being 1/n Hz and n an integer less than 60, so that the indexing means can be deflected by said other time pulses from its position of rest to a first indexing position and beyond that by the minute pulses to a second indexing position; in that a second wheel adapted to be driven by the indexing means through the intermediary of the indexing device is provided; and in that the indexing device, the minute wheel and the second wheel are so designed and mounted in relation to one another that the second wheel is indexable by way of deflection of the indexing means to its first indexing position, while the minute wheel is only indexable by way of greater deflection of the indexing means to its second indexing position. Accordingly, in the watch according to the invention, one and the same component directly (through the intermediary of the indexing device consisting, for example, of a pawl) drives both the second and the minute wheel so that the otherwise customary gear between the second wheel and the minute wheel and the bearings required therefor can be eliminated. The movement of the watch is thereby rendered not only simpler and less expensive in its manufacture, but also compacter in its design. Moreover, the provision of an output at the frequency divider contained in the pulse generator for delivering the other time pulses weaker in energy invovles no greater expenditure as far as both costs and space requirement are concerned.
Since in many cases where the second hand of a watch is read, it would be quite sufficient for it to be indexed, for example, in five-second-jumps, the other time pulses of weaker energy in a preferred embodiment of the analog watch according to the invention have a pulse series frequency of less than 1 Hz, and, more particularly, a frequency of 1/5 Hz (n is then equal to 5). Accordingly, the second wheel does not have 60, but rather only 60/n teeth, and therefore in the case of the preferred embodiment only 12 teeth. The decrease in the pulse series to below 1 Hz has the additional advantage that the energy requirement of the watch according to the invention is substantially less than in a watch in which 60 pulses per minute must be delivered to drive the second hand. This is, of course, particularly important in battery driven watches, to which the invention preferably relates. From the aforesaid, it is apparent that the term "second wheel" is not to be interpreted as a wheel which is by all means indexed each second, but rather as a wheel which drives the second hand.